Each edge of a cube is expanding at a rate of 4cm/s. a) How fast is the volume changing when the edge is 5cm? b) at what rate is the surface area changing when the edge is 7 cm?
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Originally Posted by math123456 Each edge of a cube is expanding at a rate of 4cm/s. a) How fast is the volume changing when the edge is 5cm? b) at what rate is the surface area changing when the edge is 7 cm? If is the length of one side of a cube, then its volume is . We are looking for , so that means that You know the rate at which is changing, and you know the length of the side at that instant in time. Do you think you can complete the problem now?
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